Mattress

ABSTRACT

A mattress comprises a sealed outer casing within which is mounted a resilient support formed by a composite foam core. At least an upper portion of the resilient support is formed by a visco-elastic foam. A vent is provided in a side wall of the casing and is covered by a filter which prevents ingress of bacteria into the cover A flap is mounted on the cover and in use extends down over the vent to prevent the filter being damaged by fluids.

BACKGROUND OF THE INVENTION

[0001] The invention is particularly related to a mattress which issuitable for use in medical applications for the improved comfort ofpatients who are confined to bed for long periods of time. Such patientsoften suffer from bedsores due to the concentration of pressure inregions where the patients body touches the mattress, particularly inthe regions of the shoulders, hips and heels. Another problem arising inmedical environments is the possibility of infection of the mattresswith bacteria which could subsequently infect a patient.

[0002] The present invention is directed towards overcoming theseproblems.

SUMMARY OF THE INVENTION

[0003] According to the invention there is provided a mattress,comprising an outer casing within which is mounted a resilient supportwherein the support is sealed within the casing and said casing has anair vent in a side wall of the casing. Thus, convent the casing can beformed with welded seams without ballooning of the casing Further, thevent allows the mattress to breathe.

[0004] In a particularly preferred embodiment at least an upper portionof the resilient support is formed by a visco-elastic foam.Advantageously the visco-elastic slow foam or memory foam has a tendencyto mould itself into the shape of the body lying on the foam layer, thusproviding an even distribution of pressure over the body of the patientand thus minimising localised high pressure points.

[0005] In a preferred embodiment a filter is mounted across the air ventto prevent Me ingress of bacteria to an interior of me casing. Inanother embodiment the filter has pores for through-passage of air, saidpores being sized to trap any particle greater than 1 micron in size. Asbacteria typically attaches to particles over 6 microns in size and thefilter blocks the passage of any particle than 1 micron in size, thefilter effectively prevents ingress of bacteria into the cover.

[0006] In a further embodiment a flap is mounted on the cover, the flapbeing fixed to an exterior of the cover above the vent and extendingdownwardly over the vent This advantageously protects the vent andfilter being damaged by fluid such as when cleaning the mattress forexample

[0007] The cover is preferably of an elastic material which is stretchedover the foam corn Additional anti-bacterial, fungistatic protection maybe provided for the foam more and for the cover if desired.

[0008] In a preferred embodiment of the invention at least portion ofthe foam layer has a profiled area comprising projections and hollows atan upper support surface of the foam layer.

[0009] In a particularly preferred embodiment said profiled area is at alower end of the foam layer forming a heel support region of the foamlayer. This advantageously provides extra pressure reduction in the heelarea of a patient when the mattress is in use.

[0010] In another embodiment the projections are of generallyflat-topped pyramid shape arranged in a chequered formation with hollowsformed therebetween.

[0011] In another embodiment the visco-elastic foam has a density in therange 60-95 kg/m³. Most preferably the density of the visco-elastic foamis 85 kg/m³.

[0012] In a particularly preferred embodiment the support is provided bya multi-layered support core comprising the visco-elastic foam top layermounted on at least ore bottom layer of foam having a greater resiliencethan the visco-elastic foam. This provides added rigidity and support tothe core.

[0013] In a particularly preferred embodiment the bottom layer comprisesa combustion modified high resilient foam.

[0014] Preferably the casing is of a stretchable elastic material.

[0015] In another embodiment the resilient support further includes anouter frame mounted about a side of said layers forming an endless sidemargin about said layers, said outer frame being formed of a high indexfoam.

[0016] In a particularly preferred embodiment the mattress includes acomposite resilient support having a laminated core with a rectangularbottom layer and an associated rectangular top layer superimposed onsaid bottom layer, a top face of the bottom layer engaging andadhesively secured to a complementary bottom face of the top layer, saidbottom layer being formed of a combustion modified high resilience foamand said top layer being formed of a visco-elastic foam, said layersbeing of equal depth, said core being encircled by an outer frame formedof a high index foam which extends about the side faces and end faces ofthe core and being adhesively secured thereto, a sealed casing mountedabout said core, said casing being formed of an elastic materialstretched about the core with overlapping seams of the core being weldedtogether to form a sealed enclosure about the core, an opening in saidcasing forming a vent to allow air passage between an interior and anexterior of the casing, a filter mounted across the vent and a flapmounted on the casing covering the vent and being fixed to said casingabout a periphery of the flap above and at each side of the vent leavinga downwardly facing opening between a lower end of the flap and thecasing for air passage to and from the air vent

[0017] In another aspect the invention provides a mattress comprising anouter casing within which is mounted a resilient support at least anupper portion of the support being formed by a layer of visco-elasticfoam, the support having lower end forming a heel support region of thesupport an upper surface of said heel support region being a profiledarea of projections and hollows. Preferably the projections have aflat-topped pyramid shape.

[0018] In another embodiment the support is sealed within the casing andsaid casing has an air vent in a side wall of the casing Ideally afilter is mounted across the air vent to prevent ingress of bacteria toan interior of the casing. Preferably a flap is mounted onto the casing,the flap being fixed to an exterior of the casing above the vent andextending downwardly over the vent, a free edge of the flap definingwith the casing an opening for through passage of air to and from mevent

[0019] In a further aspect the invention provides a mattress comprisingan elastic outer within which is mounted a resilient support, at leastan upper portion of the support being formed by a layer of visco-elasticfoam having a density of about 85 /m³.

[0020] In another embodiment the resilient support has a laminatedconstruction including a rectangular bottom layer and an associatedrectangular top layer superimposed on said bottom layer, a top face ofthe bottom layer engaging and being adhesively secured to acomplementary bottom face of the top layer, said bottom layer beingformed of a combustion modified high resilience foam and said top layerbeing formed by the layer of visco-elastic foam.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will be more clearly understood from the followingdescription of some embodiments thereof, given by way of example only,with reference to the accompanying drawings, in which;

[0022]FIG. 1 is a perspective view of a mattress according to theinvention;

[0023]FIG. 2 is a plan view of a composite foam core of the mattress;

[0024]FIG. 3 is a sectional view taken along the line III-III of Fig 2;

[0025]FIG. 4 is a perspective, partially cut-away view illustrating themattress;

[0026]FIG. 5 is a detail perspective view illustrating a profiledpressure reducing portion of the core;

[0027]FIG. 6 is a perspective view of another mattress:

[0028]FIG. 7 is a perspective view of a cushion according to anotherembodiment of the invention; and

[0029] FIG. B is a perspective view of a foam core of the cushion ofFIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Referring to the drawings, and initially to FIGS. 1 to 5 thereof,there is illustrated a mattress according to the invention indicatedgenerally by the reference numeral 1. The mattress 1 comprises a sealedouter casing 2 within which is mounted a resilient support formed by acomposite foam core 3. A vent 4 is provided in a side wall 7 of thecasing 2 and is covered by a filter 5, which prevents ingress ofbacteria into the cover 2. A flap 6 is mounted on the cover 2 and in useextends down over the vent 4 to prevent the filter 5 being damaged byfluids. The flap 6 is attached to the cover 2 along top and side edgesleaving at least portion of the bottom edge open to allow air passage.

[0031] The cover 2 is formed of an elastic stretchable material withseams of the cover 2 being welded to provide a sealed enclosure for thecore 3.

[0032] The foam core 3 comprises an upper layer 8 of a visco-elasticmaterial mounted on and adhesively secured to a lower layer 9 whichcomprises a combustion modified high resilience foam The upper layer Bhas a top surface 10 upon which a patient is supported in use,

[0033] A lower end of the upper layer has an anatomic profiling region12 in which material has been removed from the layer 8 to provide aserious of projections 14 and associated hollows 15 arranged in achequered configuration. The projections 14 have a generally pyramidalshape having a square flat top 16 which is substantially flush with thecontinuous portion of top surface 10 at an upper end of the upperlayers. Side walls 17 slope downwardly and outwardly of each side of thetop 15 defining hollows 15 or voids between the projections 14. In thiscase the hollows 15 extend roughly one half of the depth of the upperlayer 8. The depth of both layers 8, 9 is typically about 7 cm. Theupper visco-elastic foam layer 8 has a density of 85 kg/m³.

[0034] For added support to the core 3 an outer frame 20 is providedcomprising side pieces 21 glued to each side of the layers 8, 9 and endpieces 22 glued across the ends of the layers 8, 9. The frame 20 isformed from a high index foam material.

[0035] In use, the mattress 1 is mounted on a bad with the upper layer 8of visco-elastic foan uppermost When a patent lies on the mattress 1 theupper layer 8 tends to deform to closely conform to the contour of thepatients body to gently support and evenly distribute the weight of thepatient over a wide area. Further, the profiled region 12 on which thepatients heels rest provides extra pressure reduction in the heel am toreduce the risk of pressure sore development in this area of the body.

[0036] The flap which covers the filter and vent does not have to extendfully across the side of the casing and may simply extend over the ventand filter

[0037] It will be noted that the cover can be easily cleaned. Further,as the cover 2 is sealed bacteria cannot impregnate the mattress. Thevent and filter allows the mattress to breathe when a person lies on orgets up from the mattress and prevents ballooning of the sealed casing.

[0038] It will be appreciated that all the foams used are treated sothat they are flame retardant to British Standard Sl 1324.

[0039] Referring now to FIG. 6, there is shown another mattress 30comprising an outer cover 31 surrounding a foam support core 32 formedby three layers of foam material comprising an upper layer 33 ofvisco-elastic foam, an intermediate layer 34 and a lower layer 35 offoams of greater resilience than the visco-elastic foam.

[0040] The term “mattess” as used in this patent specification can alsobe taken to include cushions of similar construction. For example,referring to FIGS. 7 and 8. there is shown a cushion 40 according toanother embodiment of the invention The cushion 40 comprises an outercover 41 having an opening closed by a concealed zip 42 along one edge,within which is mounted a foam support core 43. The foam core 43comprises an upper layer 44 of visco-elastic foam and a lower layer 45of a combustion modified high resilience foam.

[0041] The invention is not limited to the embodiments hereinbeforedescribed, but may be varied in both construction and detail within thescope of the appended claims

1. A mattress comprising an outer casing within which is mounted aresilient support characterised in that the support is sealed within thecasing and said casing has an air vent in a side wall of the casing. 2.A mattress as claimed in claim 1 wherein at least an upper portion of beresilient support is formed by a layer of vis elastic foam.
 3. Amattress as claimed in claim 1, wherein a filter is mounted across theair vent to prevent the ingress of bacteria to an interior of thecasing.
 4. A mattress as claimed in claim 31 wherein the filter haspores for though-passage of air, said pores being sized to trap anyparticle greater than 1 micron in size.
 5. A mattress as claimed inclaim 1, wherein a flap is mounted on the casing, the flap being fixedto an exterior of the casing above the vent and extending downwardlyover the vent a free edge of be flap defining with the casing an openingfor through passage of air to and from the vent
 6. A mattress as claimedin claim 1, wherein at least portion of me resilient support has aprofiled area comprising projections and hollows at an upper surface ofthe resilient support.
 7. A mattress as claimed in claim 6 wherein saidprojections have a flat-topped pyramid shape.
 8. A mattress as claimedin claim 6, wherein said profiled area is at a lower end of theresilient support forming a heel support region of the resilientsupport.
 9. A mattress as claimed in claim 2, wherein the visco-elasticfoam has a density in the range 60-95 kg/m³.
 10. A mattress as claimedin claim 9 wherein the density of the visco-elastic foam is about 85kg/m³.
 11. A mattress as claimed in claim 1 wherein the resilientsupport includes a bottom layer of a combustion modified high resilientfoam and a top layer of visco-elastic foam.
 12. A mattress as claimed inclaim 11 wherein the resilient support further includes an outer framemounted about a side of said layers forming an endless side margin aboutsaid layers, said outer frame being formed of a high index foam.
 13. Amattress as claimed in claim 1 including a composite resilient supporthaving a laminated core with a rectangular bottom layer and anassociated rectangular top layer superimposed on said bottom layer, atop face of the bottom layer engaging and adheisively secured to acomplementary bottom face of the top layer, said bottom layer beingformed of a combustion modified high resilience foam and said top layerbeing formed of a visco-elastic foam, said layers being of equal depth,said core being encircled by an outer frame formed of a high index foamwhich extends about the side faces and end faces of the core and beingadhesively secured thereto, a sealed casing mounted about said core,said casing being formed of an elastic material stretched about the corewith overlapping seams of the cover being welded together to form asealed enclosure about the core, an opening in said casing forming avent to allow air passage between an interior and an exterior of thecasing, a filter mounted across the vent and a flap mounted on thecasing Covering the vent and being fixed to said casing about aperiphery of the flap above and at each side of the vent leaving adownwardly facing opening between a lower end of the flap and the casingfor air passage to and from the air vent
 14. A mattress comprising anouter casing within which is mounted a resilient support at least anupper portion of the support being formed by a layer of visco-elasticfoam, the support having a lower end forming a heel support region ofthe support, an upper surface of said heel support region being aprofiled area of projections and hollows.
 15. A mattress as claimed inclaim 14 wherein the projections have a flat-topped pyramid shape.
 16. Amattress as claimed in claim 14 wherein the support is sealed within thecasing and said casing has an air vent in a side wall of the casing. 17.A mattress as claimed in claim 16 wherein a filter is mounted across theair vent to prevent ingress of bacteria to an interior of the casing.18. A mattress as claimed in claim 16 wherein a flap is mounted on thecasing, the flap being fixed to an exterior of the casing above the ventand extending downwardly over the vent, a free edge of the flap definingwith the casing an opening for through passage of air to and from thevent
 19. A mattress comprising an outer elastic casing within which ismounted a resilient support, at least an upper portion of the supportbeing formed by a layer of visco-elastic foam having a density of about85 kg/m³.
 20. A mattress as claimed in claim 19 wherein the resilientsupport has a laminated construction including a rectangular bottomlayer and an associated rectangular top layer superimposed on saidbottom layer, a top face of the bottom layer engaging and beingadhesively secured to a complementary bottom face of the top layer, saidbottom layer being formed by a combustion modified high resilience foamand said top layer being formed by the layer of visco-elastic foam.